Unphysical critical curves of binary mixtures predicted with GERG models

Published

October 19, 2020

Author(s)

Ian H. Bell, Ulrich K. Deiters

Abstract

When applied to asymmetric binary mixtures (e.g., methane + pentane or heavier alkanes, hydrogen-containing mixtures), the GERG equation of state (GERG-2004 or GERG-2008) predicts critical curves with physically unreasonable temperature maxima above the critical temperature of the heavier component. These maxima are associated with physically impossible vapor–liquid equilibria. The phenomenon is probably caused by corrections for critical anomalies that were built into the empirical pure-fluid equations of state forming the foundation of the GERG model. These corrections ensure that the model represents thermodynamic data of pure fluids quite well even close to their critical points. For mixtures, however, the corrections can cause artifacts.

Citation

International Journal of Thermophysics

Volume

41

Pub Type

Journals

Download Paper

https://doi.org/10.1007/s10765-020-02743-3

Local Download

Keywords

critical points, mixtures, thermodynamics

Citation

Bell, I. and Deiters, U. (2020), Unphysical critical curves of binary mixtures predicted with GERG models, International Journal of Thermophysics, [online], https://doi.org/10.1007/s10765-020-02743-3 (Accessed October 14, 2025)